Field of the Invention
The present invention relates to a radio battery system, and a cell controller and a battery controller that have the radio battery system.
Description of Related Art
While global environmental issues have been largely highlighted, reduction of carbon dioxide gas emissions has been required in every scene to prevent global warming. Vehicles with a gasoline engine that are a major source of carbon dioxide gas emissions have begun to be replaced with hybrid electric vehicles and electric vehicles.
Since a large secondary battery that typifies power sources for hybrid electric vehicles and electric vehicles need to have a high power output and a large capacity. A battery module that composes the large secondary battery is formed of a plurality of cells connected in series.
A lithium ion battery that is a secondary battery needs to be appropriately handled to prevent it from being deteriorated due to charging at a high voltage and overdischarging. Thus, battery modules with which hybrid electric vehicles and electric vehicles are equipped have a function for measuring voltage, current, temperature, and the like to detect the states of their own cells.
FIG. 1 shows a structure of a battery module with which a hybrid electric vehicle or an electric vehicle is equipped.
As shown in the drawing, a battery module 500 is connected to a motor 570 through an inverter 560. Disposed between the battery module 500 and the inverter 560 is a relay box 550. The battery module 500 includes a plurality of cells 510, a cell controller 520 (hereinafter also referred to as “a CC”), and a battery controller 530 (hereinafter also referred to as “a BC”). Disposed between the battery controller 530 and the inverter 560 is a hybrid controller 540 that can communicate with both of the battery controller 530 and the inverter 560.
The plurality of cells 510 is connected to a CC. The CC measures states of the plurality of cells 510. A plurality of CCs is connected to a BC. The BC obtains states of the plurality of cells 510 from the plurality of CCs. The BC calculates State of Charge (SOC) and State of Health (SOH) from the obtained states of the plurality of cells 510 and notifies a host controller or the like of the calculation results.
The drawing shows that the BC and CCs communicate through wires. Japanese Patent Application Laid-Open Publication No. 2005-135762 (Patent Document 1) describes that CCs and a BC wirelessly communicate, not through wires to reduce a wiring cost, a high voltage insulation cost, and an assembling cost.
Japanese Patent Application Laid-Open Publication No. 2011-166619 (Patent Document 2) discloses an RF tag reader/writer that executes a communication process with RF tags based on a slotted ALOHA scheme that allows the device to communicate with RF tags as individual information acquisition targets at a plurality of time slots that compose a round. When the device receives a Query command, it generates a random number and decides one of the plurality of slots of one round at which it responds. The RF tag reader/writer described in Patent Document 2 is set to receive all Query-rep commands to recognize slot numbers.